A chamfering of an end edge Wa of a relatively small workpiece W, such as one shown in FIG. 1, and a peripheral edge Wc of a bore Wb therein, has conventionally been performed by a hand process, utilizing a thread-like abrasive tape. However, such method has disadvantages in that it is troublesome, time-consuming and inefficient.
As an automated method of such a processing, a processing method utilizing a sandblasting is proposed in which abrasive grains comprised of, for example, silica sand, chilled cast iron or the like are caused to strongly impinge against a workpiece surface to be processed. However, as in the case of a head for a video signal recording and reproducing apparatus, for example, in which the workpiece W has a f.sub.2 requiring a mirror finish adjacent surfaces f.sub.1 to be processed by the sandblasting, there would be a fear that the abrasive grains of the sandblasting impinge also against the surface f.sub.2 to exert a bad influence thereupon. For this reason, as matters stand, the conventionally general technology does not allow the sandblasting to be adopted for processing of the workpiece W.
Accordingly, an object of the present invention is to provide a processing method which can process, utilizing a sandblasting, a workpiece which has a surface not to be processed adjacent a surface to be processed.
Another object of the present invention is to provide an apparatus utilizing such processing method.